4-(1H-Azolylmethyl)-1,3-dioxolan-5-one derivatives, production thereof and use thereof as growth regulators and/or microbicides

ABSTRACT

The invention relates to novel 4-(1H-azolylmethyl)-1,3-dioxolan-5-one derivatives of the formula I ##STR1## and to the production and use of these compounds. In formula I, R 1  and R 2  are unsubstituted or substituted alkyl or phenyl, or together form a 3- to 7-membered carbocyclic ring which is unsubstituted or substituted, A is an unsubstituted or substituted phenyl radical, and X is --CH═ or --N═. The compounds of the formula I can be used in the form of appropriate compositions for regulating plant growth and/or for controlling and/or protecting plants from attack by phytopathogenic microorganisms.

The present invention relates to substituted4-(1H-azolylmethyl)-1,3-dioxolan-5-one derivatives of the formula I andacid addition salts thereof with organic and inorganic acids, and themetal complex salts thereof. The invention also relates to theproduction of these compounds and to growth regulating and/ormicrobicidal compositions which contain one of the compounds of formulaI as active ingredient. The invention also relates to the use ofcompounds of the formula I for regulating plant growth and/orcontrolling harmful microorganisms.

The invention comprises compounds of the formula I ##STR2## wherein eachof R₁ and R₂ independently is hydrogen, C₁ -C₈ alkyl unsubstituted ormono- or polysubstituted by halogen, C₁ -C₄ alkoxy, C₁ -C₄ alkylthio,phenyl or phenoxy, or is phenyl, all of which phenyl radicals areunsubstituted or mono- or polysubstituted by halogen, nitro,trifluoromethyl, C₁ -C₄ alkyl or methoxy, or R₁ and R₂ together form a3- or 7-membered carbocyclic ring which is unsubstituted or substitutedby halogen, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or C₁ -C₃ alkylthio. A is aphenyl radical unsubstituted or mono- or polysubstituted by halogen,trifluoromethyl, nitro, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or phenyl, and X is--CH═ or --N═, together with the acid addition salts thereof withorganic or inorganic acids, and also the metal complex salts thereof.

Accordingly, the compounds of the formula I comprise the free compounds,their acid addition salts and their metal complexes.

Depending on the indicated number of carbon atoms, alkyl by itself or asmoiety of another substituent denotes e.g. the following groups: methyl,ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl, as well as theisomers thereof, e.g. isopropyl, isobutyl, tert-butyl, isopentyl etc. A3- to 7-membered carbocyclic ring comprises e.g. cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl. Halogen generallydenotes fluorine, chlorine, bromine or iodine, with chlorine or brominebeing preferred.

Examples of salt-forming acids are inorganic acids, e.g. hydrohalicacids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid orhydriodic acid, and also sulfuric acid, phosphoric acid, phosphorousacid, nitric acid; and organic acids such as acetic acid,trifluoroacetic acid, trichloroacetic acid, propionic acid, glycolicacid, thiocyanic acid, lactic acid, succinic acid, citric acid, benzoicacid, cinnamic acid, oxalic acid, formic acid, benzenesulfonic acid,p-toluenesulfonic acid, methanesulfonic acid, salicylic acid,p-aminosalicylic acid, 2-phenoxybenzoic acid or 2-acetoxybenzoic acid.

Metal complexes of the formula I consist of the basic organic moleculeand an inorganic or organic metal salt, for example the halides,nitrates, sulfates, phosphates, acetates, trifluoroacetates,trichloroacetates, propionates, tartrates, sulfonates, salicylates,benzoates etc. of the elements of the third and fourth main group of thePeriodic Table such as aluminium, tin or lead, and of the first toeighth auxiliary group such as chromium, manganese, iron, cobalt,nickel, copper, zinc, silver, mercury etc. Preferred elements are thoseof the auxiliary groups of the fourth period. The metals can exist indifferent valency states. The metal complexes of the formula I can bemononuclear or polynuclear, i.e. they can contain one or more parts ofthe organic molecule as ligands.

The compounds of the formula I are biologically active substances whichcan be used both for influencing plant growth and for controllingharmful, in particular phytopathogenic, microorganisms. The compounds ofthe formula I thus afford the possibility of selectively regulatingplant growth and simultaneously of protecting plants from pathogens. The1,2,4-triazolyl derivatives within the scope of formula I are preferred.

On account of their pronounced growth regulating and/or microbicidalaction, preferred compounds of the formula I are those which contain thefollowing types of substituents or combinations thereof.

For R₁ and R₂ independently of each other:

(a) hydrogen, C₁ -C₈ alkyl, phenyl which is unsubstituted or substitutedby halogen, nitro, trifluoromethyl, methyl or ethyl, or benzyl; or inparticular

(b) hydrogen, C₁ -C₅ alkyl, phenyl; in particular

(c) C₁ -C₅ alkyl.

For A:

(a) phenyl, unsubstituted or mono- or polysubstituted by halogen,trifluoromethyl, nitro, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or phenyl; or inparticular:

(b) phenyl, unsubstituted or mono- or polysubstituted by halogen, C₁ -C₃alkyl, methoxy or phenyl; in particular

(c) phenyl, 2,4-dichlorophenyl, 2,4-dibromophenyl,2-chloro-4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl.

For X: --CH═ or, in particular, --N═.

A preferred group of growth regulating and/or microbicidal compoundscomprises those of the formula I, wherein each of R₁ and R₂independently is hydrogen, C₁ -C₈ alkyl, phenyl which is unsubstitutedor substituted by halogen, nitro, trifluoromethyl, methyl or ethyl, oris benzyl; A is phenyl, unsubstituted or mono- or polysubstituted byhalogen, trifluoromethyl, nitro, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or phenyl;and X is --CH═ or --N═.

A further preferred group of growth regulating and/or microbicidalcompounds comprises those of the formula I, wherein each of R₁ and R₂independently is hydrogen, C₁ -C₅ alkyl or phenyl; A is phenyl,unsubstituted or mono- or polysubstituted by halogen, C₁ -C₃ alkyl,methoxy or phenyl; and X is --CH═ or --N═.

A particularly preferred group of growth regulating and/or microbicidalcompounds comprises those of the formula I, wherein each of R₁ and R₂independently is C₁ -C₅ alkyl, A is phenyl, 2,4-dichlorophenyl,2,4-dibromophenyl, 2-chloro-4-fluorophenyl, 4-chlorophenyl or4-bromophenyl, and X is --CH═ or --N═.

Further preferred compounds of the formula I are those wherein R₁ and R₂together form a 3- to 7-membered carbocyclic ring which is unsubstitutedor substituted by methoxy.

The following individual compounds are especially preferred on accountof their pronounced growth regulating and/or microbicidal action:

4-(1H-1,2,4-triazolylmethyl)-4-(4-chlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,

4-(1H-1,2,4-triazolylmethyl)-4-(4-bromophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,

4-(1H-1,2,4-triazolylmethyl)-4-(phenyl)-2,2-dimethyl-1,3-dioxolan-5-one,

4-(1H-1,2,4-triazolylmethyl)-4-(2,4-dichlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,

4-(1H-imidazolylmethyl)-4-(4-chlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,

4-(1H-1,2,4-triazolylmethyl)-4-(4-chlorophenyl)-2,2-diethyl-1,3-dioxolan-5-one,and

4-(1H-1,2,4-triazolylmethyl)-5-(2-chloro-4-fluorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one.

The compounds of the formula I can be obtained by a method as describede.g. hereinbelow.

In the formulae II to VI above, R₁ and R₂, A and X are as defined forformula I, M is hydrogen or a metal ion, preferably the cation of analkali metal or alkaline earth metal, and G is one of the customaryleaving groups, e.g. alkoxy, benzenesulfonyloxy,p-bromobenzenesulfonyloxy, p-tosyloxy, trifluoroacetyloxy, loweralkylsulfonyloxy such as mesyloxy or, in particular, halogen such asfluorine, chlorine, bromine or iodine, with chlorine or bromine beingpreferred.

The process for obtaining compounds of the formula I can be carried oute.g. by means of the partial reactions A, B, C, D or E illustratedbelow: ##STR3## an acid II (which can either be in the form of aracemate or in its pure D- or L-form) is reacted with an open-chain orcyclic ketone or with an aldehyde of the formula (III) to give thedioxolane IV. For this reaction it is possible, in principle, to usesolvents which are inert to the reactants and advantageously formazeotropes with water. Examples of suitable solvents are aromatichydrocarbons such as benzene, toluene, xylenes or halogenatedhydrocarbons such as dichloromethane, chloroform, carbon tetrachloride,1,2-dichloroethane, tetrachloroethylene, chlorobenzene, and alsoethereal compounds such as tert-butylmethyl ether, dioxane etc. In somecases the compound of the formula III itself can be used as solvent. Thereaction temperature depends largely on the choice of ketone or aldehydeIII and be e.g. from -30° to 180° C., preferably from -10° to 140° C. Insome cases it is convenient to effect acid catalysis. Examples ofsuitable catalysts and condensation agents are mineral acids such ashydrohalic acids, sulfuric acid, phosphoric acid, sulfonic acids such asp-toluenesulfonic acid, acid ion exchange resins etc. The water formedcan be removed from the reaction mixture not only as an azeotrope butalso with the aid of ion exchange resins, molecular resins, or byreaction with dicyclohexylcarbodiimide. It is sometimes advantageous tocarry out the reaction under elevated pressure. ##STR4## the dioxolanoneIV reacts with formaldehyde, advantageously in the presence of a base,to give the intermediate of the formula V. Suitable bases for thisreaction are tertiary amines such as trialkylamines, pyridine,dimethylaniline etc., or quaternary ammonium hydroxides such astetramethylammonium hydroxide. It is possible to use e.g. an equimolaramount of base, based on the product IV. Partial reaction B can becarried out e.g. in the temperature range from -30° to +80° C., using asolvent which is inert to the reactants, e.g. an ethereal compound suchas tetrahydrofurane, dioxane etc., or a nitrile such as acetonitrile,propionitrile etc. ##STR5## a leaving group G (G can be e.g. one of thecustomary leaving groups, for example acyloxy, arylsulfonyloxy such asbenzenesulfonyloxy, p-bromobenzenesulfonyloxy, p-tosylosy oralkylsulfonyloxy, especially lower alkylsulfonyloxy such as mesyloxy, orhalogen such as fluorine, chlorine, bromine, iodine, preferably chlorineor bromine) is introduced into the molecule V by reacting theintermediate V e.g. with methanesulfonyl chloride, advantageously in thepresence of a tertiary amine such as pyridine, trialkylamine, collidineetc., to give the intermediate VI. The amine is employed in at least themolar amount, based on the compound of the formula V. The conventionalorganic halogenated and non-halogenated aliphatic and aromatic solventscan be employed in this reaction. The leaving group G can either replacethe proton or the OH group altogether.

Some of the intermediates of the formula VI have fungicidal activity,e.g. the compounds of the formula VI, wherein A is 2,4-dichlorophenyland R₁ and R₂ are alkyl, e.g. methyl. ##STR6## the leaving group G (e.g.CH₃ SO₃ -) is replaced by the substituent ##STR7## by converting e.g.the product VI with a compound ##STR8## into the final product of theformula I. The reaction can be conducted in conventional inert organicsolvents and in some cases it is convenient to add a base such as analkali metal or alkaline earth metal carbonate, an alkali alcoholate orsodium hydride. ##STR9## an alcohol of the formula V reacts either withN,N'-thiocarbonyldi-1,2,4-triazole or N,N'-thiocarbonyldiimidazoleaccompanied by the elimination of SO₂ and the corresponding heterocycleto give a final product of the formula I. It can be advantageous toconduct the reaction in a polar organic solvent, e.g. an ether oretheral compound such as diethyl ether, diisopropyl ether,tert-butylmethyl ether, dimethoxyethane, dioxane, tetrahydrofurane,anisole; a nitrile such as acetonitrile or propiononitrile; an estersuch as ethyl acetate or butyl acetate; or a dialkylamide such asdimethyl amide. Mixtures of such solvents with one another can also beemployed. The reaction can be carried out from temperatures of 20° C.upwards. To hasten the reaction, however, it is advantageous to usehigher temperatures, for example from 45° to 90° C. or the boiling pointof the solvent or mixture of solvents.

The above preparatory methods also constitute an object of theinvention.

The starting compounds of the formulae II and III are known and areobtained by methods which are generally known.

Dioxolanones of the formula IV are mentioned in the followingpublications: Org.Synth. Coll. Vol. 3, 536 (1955), Bull. Soc. Chim.France 1970, 332, Ber. 68, 303, 609 (1935), Ber. 72, 319, 798 (1939).

Dioxolanones of the formulae V and VI are novel. They have beenspecially developed for obtaining the compounds of the formula I andare, in addition, valuable intermediates for synthesing agrochemicals.Some also are biologically active and have, in particular,phytofungicidal activity. The compounds of the formulae V and VItherefore also constitute an object of the invention.

The production of α-hydroxycarboxylic acids of the formula II isdescribed in the following publications: J. Org. Chim. 33, 2565 (1968),Org. Synth. Coll. Vol. 3, 326 (1955), and Org. Synth. Coll. Vol. 3, 538(1955). 2-Methyl-2-ethyl-4-phenyl-1,3-dioxolan-5-one is known from J.Econ. Entomol. 42, 439 (1949) and2,2-dimethyl-4-phenyl-1,3-dioxolan-5-one is known from U.S. patentapplication 70 388 [CA 46, 3209d (1952)]. Insecticidal activity only isreported for both compounds.

The compounds of formula I contain, vicinal to the substituent A, anasymmetrical carbon atom *C and a further centre of asymmetry (*), if R₁and R₂ are different. The latter is adjacent to the two oxygen atoms.##STR10##

(a) If R₁ and R₂ are identical, both stereoisomers can be separated byconventional methods, e.g. fractional crystallisation of the salts ofcompounds of the formula I with an optically active acid such ascamphorsulfonic acid, into the optical antipodes. However, the sameobjective can also be achieved by a selective synthesis of theenantiomers, starting from an optically pure hydroxycarboxylic acid II(partial reaction A).

(b) If R₁ and R₂ are different, then 4 stereoisomers are obtained. Ifdesired, separation of the pairs of diastereomers (cis-trans isomers)into the racemates can also be efffcted by conventional methods, e.g.,by column chromatography. A further separation of the pure diastereomers(cis-trans isomers) into the optically pure enantiomers can be carriedout by the separation method described in (a).

The individual configurations can be characterised spectroscopically,e.g. by NMR spectroscopy or X-ray structural analysis. The presentinvention relates to all isomers, their salts and metal complexes.

Surprisingly, it has now been found that the novel compounds of theformula I and compositions containing them are characterised inparticular by their selective influence on plant metabolism. Thisselective influence on the physiological processes of plant developmentmakes it possible to use the compounds of formula I for differentpurposes, especially for those in connection with increasing the yieldof useful plants, with faciliating harvesting, and with labour-saving inmeasures taken in crops of cultivated plants.

The compounds of the formula I disclosed herein can be used forregulating the growth of plants. Previous experience with theapplication of growth regulators has shown that the active ingredientscan act on the plants in one or more different ways. These differentactions depend largely on the time of application, i.e. on thedevelopment stage of the seed or plant, on the nature of theapplication, and, in particular, on the concentrations employed. Suchactions, however, differ in turn from one type of plant to another.Accordingly, the application of compounds of the formula I affords thepossibility of influencing the growth of plants in the manner desired.

The novel compounds of the formula I and compositions containing theminhibit the vegetative growth of plants and are thereby able to increasethe crop yield substantially. For example, the vegetative growth ofsoybean plants and other leguminosae such as beans, peas or lentils isreduced and the generative growth promoted, resulting in a directincrease in crop yield. The vegetative growth of other varieties ofplants, e.g. vines, cereals, grasses and ornamentals, is inhibited indesired manner. In addition, a marked strengthening of the supportingtissue of the treated plants is observed.

An important kind of plant regulation resides in the special property ofcompounds of the formula I, when used in rates of application of 0.2 to5 kg a.i./ha, of effecting in specific plants, especially in cerealcops, a selective growth inhibition which substantially increases thebreaking strength of the plants while the crop yield remains unchanged.This results in an economically very interesting method of protectingcrops against lodging caused by storms or adverse weather conditions.Moreover, a selective inhibition of the vegetative growth of manycultivated plants permits more plants to be grown per unit of area,which results in a pronounced crop yield with the same fruit setting andthe same crop area. The use of growth inhibitors also results in a moreeffective utilisation of nutrients, which then increasingly benefit theflower formation and fructification. In this manner it is possible toachieve higher crop yields with a simultaneous reduction in the amountof plant residues (e.g. straw, potato haulm, beet leaves).

Particular attention is also drawn to the possibility of inhibiting theundesired growth of suckers in different species of plants, especiallyin tobacco plants, with the compounds and compositions of the invention,when the leading shoot has been cut off shortly before flowering inorder to bring about the desired increase in growth of the leaves.

In contrast to the effects described hitherto obtained with thecompounds of the invention at low concentrations, a higher rate ofapplication, e.g. 5 to 10 kg a.i./ha, results in a very pronouncedgrowth reduction--or even in dwarfism--in a number of monocots anddicots. From the standpoint of maintaining arable land, this effectprovides a particularly advantageous method of inhibiting harmful plantsto the extent that, independently of the growth of useful plants, auniform low plant cover is retained, which counteracts soil erosion bywind or water. This field of use includes in particular the reduction ingrowth of grasses in connection with the maintenance of pure grasscultivations such as those established in public parks and open spaces,in urban areas, industrial sites or along trunk roads, on railwayembankments or on the embankments of water bodies. In all these cases itis usually necessary to cut the turf or grass periodically. Thisoperation is not only very time-consuming, complicated and expensive inrespect of labour and machinery, but also involves the personnelconcerned and road users in considerable hazard in the traffic sector.

For this reason there is an urgent need in areas with extensive trafficnetworks, on the one hand to maintain and cultivate the grassy coveringnecessary for strengthening road shoulders and embankments on trafficroutes and, on the other, to keep it at average height by simple meansduring the entire vegetation period. This need is fulfilled in a veryadvantageous manner by applying the compounds of the formula I.

In addition to the growth inhibiting properties, the compounds of theformula I are also able in some cases to influence plant metabolism. Inthis manner the use of growth inhibitors is able to bring about animprovement in the quality of crop products. In addition to increasingthe size and weight, it is possible to increase e.g. the protein contentof leguminosae such as beans, lentils, peas and, in particular, ofsoybeans.

Further, the compounds of the formula I favourably influence germinationcapacity, flower formation and fruit development. Application of thecompounds of the invention does not bring about any change in the lifecycle of the plant which is determined by genetic characteristics, i.e.it does not cause mutation.

Surprisingly, it has also been observed that the compounds of theformula I and compositions containing them have, for practical purposes,a very advantageous microbicidal spectrum in addition to theiradvantageous growth regulating properties. Accordingly, a further fieldof use of compounds of the formula I is the control of harmfulmicroorganisms, especially of phytopathogenic fungi. Accordingly, thesecompounds have a very useful curative and preventive action forprotecting cultivated plants without adversely affecting these byundesirable side-effects. Examples of cultivated plants within the scopeof this invention are: cereals (wheat, barley, rye, oats, rice), beet(sugar beet and fodder beet), dropes, pomes and soft fruit (apples,pears, plums, peaches, almonds, cherries, strawberries, rasberries andblackberries), leguminous plants (beans, lentils, peas, soybeans), oilplants (rape, mustard, poppy, olives, sunflowers, coconuts, castor oilplants, cocoa beans, groundnuts), cucumber plants (cucumber, marrows,melons), fibre plants (cotton, flax, hemp, jute), citrus fruit (oranges,lemons, grapefruit, mandarins), vegetables (spinach, lettuce, asparagus,cabbages, carrots, onions, tomatoes, potatoes, paprika), or plants suchas maize, tobacco, nuts, coffee, sugar cane, tea, vines, hops, bananasand natural rubber plants. Within the scope of this invention, plantsare also all kinds of greenery, whether ornamentals, areas of grass,embankments or low soil covers in general which counteract erosion ordrying out of the soil, and the soil covers desired in cultivations oftrees and perennials (fruit plantations, hop plantations, maize fields,vineyards etc.).

With the compounds of formula I it is possible to inhibit or destroy themicroorganisms which occur in plants or parts of plants (fruit,blossoms, leaves, stems, tubers, roots) in these or related crops ofuseful plants, and also to protect from attack by such microorganismsthe parts of plants that grow later.

The compounds of the formula I effective, inter alia, against thephytopathogenic fungi which belong to the following classes:against theOomycetes belonging to the class of the Phycomycetes (e.g.Phytophthora); against fungi imperfecti, e.g. Cercospora; and especiallyagainst the Erysiphe and Venturia pathogens belonging to the class ofthe Ascomycetes, as well as against Basidiomycetes, in particular rustfungi such as Puccinia.

In addition the compounds of formula I have a systemic action. They canalso be used as seed dressing agents for protecting seeds (fruit,tubers, grains) and plant cuttings from fungus infections and fromphytopathogenic fungi which occur in the soil.

By far the greatest advantage in the practical use of compounds of theformula I in the field of agriculture consists in the fact that twoimportant problems, namely on the hand the strengthening of the plant inthe form of a morphological stabilisation and, on the other, theprotection of the plant against diseases, are solved simultaneously, insimple manner, by the application of a single compound or composition inthe concentration range from 0.05 to 5 kg a.i./ha, preferably from 0.2to 5 kg a.i./ha. The use of the compounds of the invention accordinglysubstantially reduces the impact on the environment. In addition, thereis the direct effect, observed in most cases, of a marked increase inthe crop yield of cultivated plants.

The invention thus relates to the use of the compounds of the formula Ifor regulating plant growth and/or for controlling and/or preventingattack by microorganisms.

The compounds of the formula I can be applied to the area or plant to betreated, simultaneously or in succession, with further compounds. Thesecompounds can be both fertilisers or micronutrient donors or otherpreparations that influence plant growth. They can also be selectiveherbicides, insecticides, fungicides, bactericides, nematicides,mollusicides or mixtures of several of these preparations, if desiredtogether with further carriers, surfactants or application-promotingadjuvants customarily employed in the art of formulation. Suitablecarriers and adjuvants can be solid or liquid and correspond to thesubstances ordinarily employed in formulation technology, e.g. naturalor regenerated mineral substances, solvents, dispersants, wettingagents, tackifiers, binders or fertilisers.

Surfactants shall be understood as meaning here surface-active compoundswhich are usually dissolved or dispersed in a liquid and are preferablyadsorbed at interfaces. A surfactant molecule contains at least onegroup having affinity for substances of strong polarity--therebygenerally causing solubility in water--and at least one further grouphaving weak affinity for water. Surfactants are therefore moleculescontaining a hydrophobic (i.e. lipophilic) component, usually ahydrocarbon radical containing alkyl or aryl moieties, and a hydrophilic(i.e. lipophobic) component, e.g. a perfluoroalkyl radical. The productsused in actual practice are usually mixtures of these compounds.Surfactants permit not only a dispersion of the active ingredient in aliquid, e.g. aqueous, medium, but also an increased wettability of theplants, which results in a reduction of the amount of active ingredientin the ready-for-use composition and consequently in a lesserenvironmental impact.

The content of active ingredient in commercial compositions is from0.01% to 90% by weight and that of adjuvants is 10 to 99.99% by weight,these latter generally comprising 0 to 30% by weight of a surfactant.

The invention also relates to compositions which contain a compound ofthe formula I as at least one active ingredient, and to the use of suchcompositions for regulating plant growth and/or for controlling and/orpreventing attack by microorganisms. In addition, the invention alsorelates to the preparation of said compositions, which compriseshomogeneously mixing the active ingredient with one or more substancesor groups of substances as described herein. The invention furtherrelates to a method of treating plants, which comprises applying theretothe compounds of the formula I or compositions containing them.

The invention is illustrated in more detail by the following Examples,in which percentages are by weight. Unless specifically stated to thecontrary, reference to a compound of the formula I will always mean themixture of racemates or diastereomers. If there is no selectivesynthesis of pure isomers, then a compound of the formula I is alwaysobtained as a mixture of all possible isomers.

PREPARATORY EXAMPLES EXAMPLE 1

(a) Preparation of a starting material ##STR11## 51.6 g (0.2 mole) of2,4,1',1'-tetrachloroacetophenone are added dropwise at 60° C. over 30minutes to a solution of 29.4 g of sodium hydroxide in 300 ml of water,while keeping the reaction temperature at 60° C. by controlling the rateof addition. The mixture is subsequently stirred for 1 hour, filtered,and then 37% hydrochloric acid is added. After repeated extraction withdiethyl ether, the combined extracts are washed with water and driedover sodium sulfate, then filtered and evaporated to dryness, affordingcolourless crystals with a melting point of 107°-111° C.

(b) Preparation of the intermediate ##STR12##2,2-dimethyl-4-(2,4-dichlorophenyl)-1,3-dioxolan-5-one A solution of 221g (1 mole) of 2,4-dichloromandelic acid and 450 ml of acetone is cooledto -10° to -20° C. and then 100 g (54.3 ml) of 98% sulfuric acid areadded dropwise. The mixture is then stirred for 2 hours at -20° C. Thereaction mixture is then poured into a solution of 200 g of sodiumcarbonate in 1.8 liters of water and the precipitate is collected byfiltration, washed with water and dissolved in methylene chloride. Themethylene chloride solution is dried over sodium sulfate and the solventis removed, yielding the title compound with a melting point of 57°-58°C.

(c) Preparation of the intermediate ##STR13##2,2-dimethyl-4-(2,4-dichlorophenyl)-4-hydroxymethyl-1,3-dioxolan-5-one

104.4 g (0.4 mole) of2,2-dimethyl-4-(2,4-dichlorophenyl)-1,3-dioxolan-5-one are dissolved in700 ml of pyridine and to the solution are added 48 g ofparaformaldehyde. Then 40 ml of a 40% solution of tetramethylammoniumhydroxide in methanol are slowly added dropwise. The mixture is stirredfor 12 hours, cooled to -5° C., and a solution of 100 ml of glacialacetic acid and 400 ml of pyridine is added dropwise until the pH valueis 6.5 to 7. The reaction solution is poured into ice-water andextracted with methylene chloride. The extract is dried over sodiumsulfate and the product is crystallised by addition of diethyl ether.The crystalline precipitate is washed with a small amount of diethylether and petroleum ether. It has a melting point of 182°-185° C.

(d) Preparation of the intermediate ##STR14##2,2-dimethyl-4-(2,4-dichlorophenyl)-4-methanesulfonyloxymethyl-1,3-dioxolan-5-one

63.5 g (0.22 mole) of2,2-dimethyl-4-(2,4-dichlorophenyl)-4-hydroxymethyl-1,3-dioxolan-5-oneare dissolved in 400 ml of pyridine and to this solution are added 28.9g of methanesulfonyl chloride at 0° to 5° C. The resultant suspension isstirred for 2 hours at the same temperature, then poured into ice-waterand extracted with methylene chloride. The extract is washed with water,dried over sodium sulfate and evaporated to dryness. The residual resinis crystallised by addition of a small amount of diethyl ether/hexaneand the product is isolated by filtration. Melting point: 98°-100° C.

(e) Preparation of the final product ##STR15##4-(1H-1,2,4-triazolylmethyl)-4-(4-chlorophenyl)-2,2-diethyl-1,3-dioxolan-5-one

With stirring and under nitrogen 5.2 g of sodium hydride (55% dispersionin oil) are added to 50 ml of absolute dimethyl formamide and then 16.6g of 1,2,4-triazole are added dropwise, whereupon elemental hydrogenescapes. The reaction mixture is heated for 2 hours to 70° C., thencooled to room temperature and a solution of 29 g (0.08 mole) of2,2-diethyl-4-(chlorophenyl)-4-methanesulfonyloxymethyl-1,3-dioxolan-5-onein 50 ml of dimethyl formamide are added dropwise. The mixture is thenheated until the reaction is complete. The reaction solution is cooledand, after addition of 100 ml of ice-water, the mixture is poured intoice-water. The precipitate is isolated by filtration and dissolved inmethylene chloride. The methylene chloride solution is washed with waterand dried over sodium sulfate and evaporated to dryness to form a resin,which crystallises by addition of a small amount of diethyl ether. Thecrystals are collected by filtration and washed with petroleum ether.Compound IX has a melting point of 105°-108° C.

The following final products of the formula I as well as intermediatesof the respective formula are prepared in analogous manner:

                                      TABLE 1                                     __________________________________________________________________________    (Final products)                                                               ##STR16##                              (XII)                                 Compound                                                                            R.sub.1                                                                              R.sub.2    R.sub.n                                                                              X  Physical data (°C.)                  __________________________________________________________________________    1.1   CH.sub.3                                                                             CH.sub.3   H      N  m.p. 115-116°                        1.2   CH.sub.3                                                                             CH.sub.3   2,4-di-Cl                                                                            N  m.p. 153-155°                        1.3   C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                          4-Cl   N  m.p. 105-108°                        1.4   C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                          4-Cl   CH m.p. 84-88°                          1.5   CH.sub.3                                                                             CH.sub.3   4-Br   N  m.p. 125-128°                        1.6   CH.sub.3                                                                             C.sub.4 H.sub.9n                                                                         2,4-di-Cl                                                                            N  m.p. 78-85°                          1.7   CH.sub.3                                                                             C.sub.2 H.sub.5                                                                          2,4-di-Cl                                                                            N  m.p. 138-142°                        1.8   CH.sub.3                                                                             C.sub.3 H.sub.7i                                                                         2,4-di-Cl                                                                            N  m.p. 68-71°                          1.9   C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                          2,4-di-Cl                                                                            N  m.p. 126-128°                        1.10  CH.sub.3                                                                             C.sub.5 H.sub.11n                                                                        2,4-di-Cl                                                                            N                                              1.11  C.sub.5 H.sub.11n                                                                    C.sub.5 H.sub.11n                                                                        2,4-di-Cl                                                                            N                                              1.12  CH.sub.3 (CH.sub.2).sub.8                                                            CH(CH.sub.2).sub.8                                                                       2,4-di-Cl                                                                            N                                              1.13  CH.sub.3                                                                             CH.sub.3   2-Cl, 4-F                                                                            N  m.p. 144-150°                        1.14  CH.sub.3 (CH.sub.2).sub.8                                                            CH.sub.3 (CH.sub.2).sub.8                                                                2,4-di-Cl                                                                            CH                                             1.15  H      H          2,4-di-Cl                                                                            CH                                             1.16  C.sub.3 H.sub.7 (n)                                                                  C.sub.3 H.sub.7 (n)                                                                      2,4-di-Cl                                                                            N  m.p. 135-139°                        1.17  H      H          H      N  resin                                       1.18  H                                                                                     ##STR17## 2,4-di-Cl                                                                            N                                              1.19  H                                                                                     ##STR18## 2,4-di-Cl                                                                            CH                                             1.20  H                                                                                     ##STR19## 2,4-di-Cl                                                                            N                                              1.21  H                                                                                     ##STR20## 2,4-di-Cl                                                                            N                                              1.22  H                                                                                     ##STR21## 2,4-di-Cl                                                                            CH                                             1.23  H                                                                                     ##STR22## 2,4-di-Cl                                                                            N                                              1.24  H                                                                                     ##STR23## 2,4-di-Cl                                                                            N                                              1.25  H                                                                                     ##STR24## 2,4-di-Cl                                                                            N                                              1.26  H                                                                                     ##STR25## 2,4-di-Cl                                                                            CH                                             1.27  CH.sub.3                                                                              ##STR26## 2,4-di-Cl                                                                            N                                              1.28  CH.sub.3                                                                              ##STR27## 2,4-di-Cl                                                                            N                                              1.29  CH.sub.3                                                                              ##STR28## 2,4-di-Cl                                                                            N                                              1.30  CH.sub.3                                                                              ##STR29## 2,4-di-Cl                                                                            N                                              1.31  CH.sub.3                                                                              ##STR30## 2,4-di-Cl                                                                            N                                              1.32  CH.sub.3                                                                              ##STR31## 2,4-di-Cl                                                                            CH                                             1.33  CH.sub.3                                                                              ##STR32## 2,4-di-Cl                                                                            N                                              1.34  CH.sub.3                                                                              ##STR33## 2,4-di-Cl                                                                            CH                                             1.35  H                                                                                     ##STR34## 4-Cl   N  m.p. 120-122°                        1.36  H                                                                                     ##STR35## 4-CH.sub.3                                                                           N                                              1.37  H                                                                                     ##STR36## 2,5-di-CH.sub.3                                                                      N                                              1.38  CH.sub.3                                                                             CH.sub.3   4-Cl   N                                              1.39  H                                                                                     ##STR37## 2-F    CH                                             1.40  H                                                                                     ##STR38## 4-OCH.sub.3                                                                          N                                              1.41  H      H          2,5-di-CH.sub.3                                                                      N                                              1.42  H      H          2,5-di-CH.sub.3                                                                      CH                                             1.43  CH.sub.3                                                                             C.sub.5 H.sub.11n                                                                        2,5-di-CH.sub.3                                                                      N                                              1.44  CH.sub.3                                                                              ##STR39## 4-Cl   N                                              1.45  H                                                                                     ##STR40## 4-Cl   N                                              1.46  CH.sub.3                                                                              ##STR41## 4-Cl   N                                              1.47  C.sub. 2 H.sub.5                                                                      ##STR42## 4-Cl   N                                              1.48  H      CCl.sub.3  4-Cl   N                                              1.49  H      CBr.sub.3  2,4-di-Cl                                                                            N                                              1.50                                                                                 ##STR43##                                                                            ##STR44## 2,4-di-Cl                                                                            N                                              1.51  CH.sub.3                                                                              ##STR45## 2,4-di-Cl                                                                            N                                              1.52  CH.sub.3                                                                              ##STR46## 2,4-di-Cl                                                                            N                                              1.53  CH.sub.3                                                                             CH.sub.3   4-NO.sub.2                                                                           N                                              1.54  H                                                                                     ##STR47## 2,4-di-Cl                                                                            N                                              1.55  H      C.sub.3 H.sub.7n                                                                         2,4-di-Cl                                                                            N                                              1.56  H                                                                                     ##STR48## 2,4-di-Cl                                                                            N                                              1.57  CH.sub.3                                                                              ##STR49## 2,4-di-Cl                                                                            N                                              1.58  CH.sub.3                                                                              ##STR50## 2,4-di-Cl                                                                            CH                                             1.59  CH.sub.3                                                                             CH.sub.2OCH.sub.3                                                                        2,4-di-Cl                                                                            N                                              1.60  CH.sub.3                                                                             CH.sub.2OCH.sub.3                                                                        4-Cl   CH                                             1.61  CH.sub.3                                                                             CH.sub.3   2-OCH.sub.3                                                                          N                                              1.62  CH.sub.3                                                                             CH.sub.3   4-OCH.sub.3                                                                          N                                              1.63  CH.sub.3                                                                             CH.sub.3   2-OCH.sub.3                                                                          CH                                             1.64  C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                          2-OCH.sub.3                                                                          N                                              1.65  CH.sub.3                                                                             CH.sub.3   2,4-di-OCH.sub.3                                                                     N                                              1.66  CH.sub.3                                                                             CH.sub.3   2-OC.sub.2 H.sub.5                                                                   N                                              1.67  H      H          2-OCH.sub.3                                                                          CH                                             1.68  H      H          2-OC.sub.3 H.sub.7i                                                                  N                                              1.69  CH.sub.3                                                                             CH.sub.3   2-OC.sub.3 H.sub.7i                                                                  N                                              1.70  C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                                                                          4-OC.sub.3 H.sub.7i                                                                  N                                              __________________________________________________________________________

                  TABLE 1a                                                        ______________________________________                                        (Final products)                                                               ##STR51##                   (XIII)                                                                              Physical data                              Compound R.sub.n   Y          X    (°C.)                               ______________________________________                                        1.71     2,4-di-Cl                                                                                ##STR52## N    m.p. 132-135°                       1.72     2,4-di-Cl                                                                                ##STR53## N                                               1.73     2,4-di-Cl                                                                                ##STR54## N                                               1.74     2,4-di-Cl                                                                                ##STR55## N                                               1.75     2,4-di-Cl                                                                                ##STR56## CH                                              1.76     4-Cl                                                                                     ##STR57## N                                               1.77     2,5-Di-Cl                                                                                ##STR58## N                                               1.78     4-Br                                                                                     ##STR59## N    m.p. 137-138°                       ______________________________________                                    

                                      TABLE 2                                     __________________________________________________________________________    (Intermediates)                                                                ##STR60##                         (XIV)                                      Com-                           Physical data                                  pound R.sub.1                                                                             R.sub.2                                                                            R.sub.n                                                                             R.sub.4 (°C.)                                   __________________________________________________________________________    2.1   CH.sub.3                                                                            CH.sub.3                                                                           H     H       m.p. 42-43°                             2.2   CH.sub.3                                                                            CH.sub.3                                                                           H     CH.sub.2 OH                                                                           viscous oil                                    2.3   CH.sub.3                                                                            CH.sub.3                                                                           H     CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 65-71°                             2.4   CH.sub.3                                                                            CH.sub.3                                                                           2,4-Di-Cl                                                                           H       m.p. 57-58°                             2.5   CH.sub.3                                                                            CH.sub.3                                                                           2,4-Di-Cl                                                                           CH.sub.2 OH                                                                           m.p. 181-182°                           2.6   CH.sub.3                                                                            CH.sub.3                                                                           2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 95-100°                            2.7   C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    4-Cl  H       b.p. 130-132°/                                                         0.7 torr                                       2.8   C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    4-Cl  CH.sub.2 OH                                                                           m.p. 83-84°                             2.9   C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    4-Cl  CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 60-63°                             2.10  CH.sub.3                                                                            C.sub.4 H.sub.9n                                                                   2,4-di-Cl                                                                           H       viscous oil                                    2.11  CH.sub.3                                                                            C.sub.4 H.sub.9n                                                                   2,4-di-Cl                                                                           CH.sub.2 OH                                                                           resin                                          2.12  CH.sub.3                                                                            C.sub.4 H.sub.9n                                                                   2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          2.13  C.sub.3 H.sub.7n                                                                    C.sub.3 H.sub.7n                                                                   2,4-di-Cl                                                                           H       m.p. 41-43°                             2.14  C.sub.3 H.sub.7n                                                                    C.sub.3 H.sub.7n                                                                   2,4-di-Cl                                                                           CH.sub.2 OH                                                                           resin                                          2.15  C.sub.3 H.sub.7n                                                                    C.sub.3 H.sub.7n                                                                   2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 49-51°                             2.16  C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    2,4-di-Cl                                                                           H       b.p. 146-148°/                                                         0.8 torr                                       2.17  C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    2,4-di-Cl                                                                           CH.sub.2 OH                                                                           m.p. 129-132°                           2.18  C.sub.2 H.sub.5                                                                     C.sub.2 H.sub.5                                                                    2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 75-77°                             2.19  H     CCl.sub.3                                                                          2,4-di-Cl                                                                           H       m.p. 90-94°                             2.20  CH.sub.3                                                                            CH.sub.3                                                                           4-Br  H       m.p. 62-64°                             2.21  CH.sub.3                                                                            CH.sub.3                                                                           4-Br  CH.sub.2 OH                                                                           m.p. 123-127°                           2.22  CH.sub.3                                                                            CH.sub.3                                                                           4-Br  CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 73-76°                             2.23  CH.sub.3                                                                            CH.sub.3                                                                           4-Br  CH.sub.2 OTosyl                                                                       m.p. 67-70°                             2.24  CH.sub.3                                                                            C.sub.3 H.sub.7i                                                                   2,4-di-Cl                                                                           H       resin                                          2.25  CH.sub.3                                                                            C.sub.3 H.sub.7i                                                                   2,4-di-Cl                                                                           CH.sub.2 OH                                                                           resin                                          2.26  CH.sub.3                                                                            C.sub.3 H.sub.7i                                                                   2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          2.27  H     C.sub.6 H.sub.5                                                                    4-Cl  H       m.p. 78-81°                             2.28  H     C.sub.6 H.sub.5                                                                    4-Cl  CH.sub.2 OH                                                                           resin                                          2.29  H     C.sub.6 H.sub.5                                                                    4-Cl  CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          2.30  CH.sub.3                                                                            CH.sub.3                                                                           2,4-di-Cl                                                                           H       m.p. 61-63°                             2.31  H     H    H     H       oil                                            2.32  H     H    H     CH.sub.2 OH                                                                           resin                                          2.33  H     H    H     CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          2.34  (CH.sub.2).sub.5                                                                         2,4-di-Cl                                                                           H       m.p. 60-66°                             2.35  (CH.sub.2).sub.5                                                                         2,4-di-Cl                                                                           CH.sub.2 OH                                                                           resin                                          2.36  (CH.sub.2).sub.5                                                                         2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          2.37  (CH.sub.2).sub.5                                                                         4-Br  H       m.p. 79-81°                             2.38  (CH.sub.2).sub.5                                                                         4-Br  CH.sub.2 OH                                                                           resin                                          2.39  (CH.sub.2).sub.5                                                                         4-Br  CH.sub.2 OSO.sub.2 CH.sub.3                                                           m.p. 65-68°                             2.40  (CH.sub.2).sub.4                                                                         2,4-di-Cl                                                                           H       m.p. 59-61°                             2.41  (CH.sub.2).sub.4                                                                         2,4-di-Cl                                                                           CH.sub.2 OH                                                                           resin                                          2.42  (CH.sub.2).sub.4                                                                         2,4-di-Cl                                                                           CH.sub.2 OSO.sub.2 CH.sub.3                                                           resin                                          __________________________________________________________________________

For application, the compounds of the formula I can be processed to thefollowing formulations:

FORMULATION EXAMPLES EXAMPLE 2

Solid formulations:

Dusts and tracking powders contain in general up to 10% of activeingredient. A 5% dust can consist for example of 5 parts of activeingredient and 95 parts of an adjuvant, such as talcum, or of 5 parts ofactive ingredient, 3 parts of highly dispersed silica and 92 parts oftalcum. Further mixtures with these and other carriers and adjuvantscommonly employed in the art of formulation are also possible. Thesedusts are produced by mixing and grinding the active ingredients withthe carriers and adjuvants, and can be applied in this form by dusting.

Granulates, such as coating, impregnated and homogeneous granulates andalso pellets, usually contain 1 to 80% of active ingredient. A 5%granulate can thus be composed of e.g. 5 parts of active ingredient,0.25 part of epoxidised vegetable oil, 0.25 part of cetyl polyglycolether, 3.50 parts of polyethylene glycol and 91 parts of kaolin(preferred particle size 0.3-0.8 mm). The granulate can be prepared asfollows: The active ingredient is mixed with the vegetable oil, themixture is dissolved in 6 parts of acetone, and the polyethylene glycoland cetyl polyglycol ether are added. The solution obtained is sprayedonto kaolin, and the acetone is subsequently evaporated off in vacuo. Amicrogranulate of this type is advantageously used for controlling soilfungi.

EXAMPLE 3

Liquid formulations:

A distinction is generally made between active ingredient concentrateswhich are dispersible or soluble in water, and aerosols. Activeingredient concentrates dispersible in water include e.g. wettablepowders and pastes, which usually contain 25-90% of active ingredient incommercial packs, and 0.01 to 15% of active ingredient in ready-for-usesolutions. Emulsifiable concentrates contain 10 to 50% of activeingredient, and solution concentrates contain in ready-for-use solution0.0001 to 20% of active ingredient. A 70% wettable powder can thus becomposed of e.g. 70 parts of active ingredient, 5 parts of sodiumdibutylnaphthalene sulfonate, 3 parts of naphthalenesulfonicacid/phenolsulfonic acid/formaldehyde condensate (in the ratio of3:2:1), 10 parts of kaolin and 12 parts of chalk, for example Champagnechalk. A 40% wettable powder can consist e.g. of the followingsubstances: 40 parts of active ingredient, 5 parts of sodiumlignosulfonate, 1 part of sodium dibutylnaphthalenesulfonate and 54parts of silicic acid. A 25% wettable powder can be formulated indifferent ways. It can be composed e.g. of: 25 parts of activeingredient, 4.5 parts of calcium lignosulfonate, 1.9 parts of chalk, forexample a mixture of Champagne chalk/hydroxyethylene cellulose (1:1),1.5 parts of sodium dibutylnaphthalenesulfonate, 19.5 parts of silicicacid, 19.5 parts of Champagne chalk and 28.1 parts of kaolin. A 25%wettable powder can also consist of e.g.: 25 parts of active ingredient,2.5 parts of isooctylphenoxy-polyoxyethylene-ethanol, 1.7 parts of amixture of Champagne chalk/hydroxyethyl cellulose (1:1), 8.3 parts ofsodium silicate, 16.5 parts of kieselguhr and 46 parts of kaolin. A 10%wettable powder can be formulated e.g. from: 10 parts of activeingredient, 3 parts of a mixture of the sodium salts of saturated fattyalcohol sulfonates, 5 parts of naphthalenesulfonic acid/formaldehydecondensate and 82 parts of kaolin. Other wettable powders can beformulated as mixtures of 5 to 30% of active ingredient together with 5parts of an absorbent carrier material, such as silicic acid, 55 to 80parts of a carrier such as kaolin, and a dispersing agent mixtureconsisting of 5 parts of sodium arylsulfonate and 5 parts of analkylaryl polyglycol ether. A 25% emulsifiable concentrate can containe.g. the following emulsifiable substances: 25 parts of activeingredient, 2.5 parts of epoxidised vegetable oil, 10 parts of a mixtureof an alkylarylsulfonate and a fatty alcohol polyglycol ether, 5 partsof dimethyl formamide and 57.5 parts of xylene. Emulsions of the desiredconcentration can be prepared from such concentrates by dilution withwater. These emulsions are particularly suitable for leaf application.It is, moreover, possible to produce further wettable powders havingother mixture ratios and containing other carriers and adjuvantscustomarily employed in formulation technology. The active ingredientsare intimately mixed in suitable mixers with the stated adjuvants, andsubsequently ground on the appropriate mills and rollers. Wettablepowders having excellent wetting and suspension properties are obtained:These wettable powders can be diluted with water to obtain suspensionsof the desired concentration, and are particularly suitable for leafapplication. The invention also relates to such compositions.

Compositions formulated as described above and containing a compound ofthe formula I as active ingredient (e.g. compounds 1.1 to 1.9, 1.13,1.16, 1.35, 1.38, 1.71 or 1.78) can be used very successfully forregulating plant growth and/or for controlling phytopathogenicmicroorganisms. Other compounds of Tables 1 and 1a can also be used withequally good or similar success.

BIOLOGICAL EXAMPLES

The spray mixtures used in the following Examples were formulated asdescribed above.

EXAMPLE 4 Growth inhibition of cereals

Summar barley (Hordeum vulgare) and summer rye (Secale) are sown insterilised soil in plastic beakers in a greenhouse and watered asrequired. The cereal shoots are treated about 21 days after sowing withan aqueous spray mixture of a compound of the formula I. Theconcentration corresponds to 0.5 and 2.5 kg respectively of activeingredient per hectare. Evaluation of the growth of the cereals is made10 and 21 days after application. Compared with untreated controls, thegrowth of cereal plants treated with compounds of the formula I isgreatly reduced. Particularly effective compounds of the formula I arethose in which the substituent A is an unsubstituted or ahalogen-substituted phenyl radical. They include compounds 1.1 to 1.9,1.38, 1.71 and 2.9.

EXAMPLE 5 Growth inhibition of grasses

Seeds of the grasses Lolium perenne, Poa pratensis, Festuca ovina, andCynodon dactylon are sown in plastic dishes filled with anearth/peat/sand mixture (6:3:1), in a greenhouse, and watered asrequired. The emergent grasses are cut back weekly to a height of 4 cmabove the soil and, 50 days after sowing and 1 day after the last cut,are sprayed with an aqueous spray mixture of an active ingredient of theformula I. The concentration of active ingredient corresponds to a rateof application of 2.5 kg per hectare. The growth of the grasses isevaluated 10 and 21 days after application. The compounds of Tables 1and 1a effect a marked reduction in growth, especially compounds 1.1 to1.9, 1.38, 1.71 and 2.9.

EXAMPLE 6 Increase in crop yield by regulating the growth of soybeans

Soybeans of the "Hark" variety are sown in plastic containers in anearth/peat/sand mixture (6:3:1). The containers are put into a climaticchamber and the plants develop to the 5-6 trefoil leaf stage after about5 weeks by optimum control of temperature, light, fertiliser addition,and watering. The plants are then sprayed with an aqueous mixture of acompound of the formula I until thoroughly wetted. Evaluation is madeabout 5 weeks after application. Compared with untreated controls, thecompounds of the formula I markedly increase the number and weight ofthe harvested siliques. Compounds 1.1 to 1.9, 1.38, 1.71 and 2.9 areparticularly effective.

EXAMPLE 7 Action against Erysiphe graminis on barley

(a) Residual protective action

Barley plants about 8 cm in height are sprayed with a spray mixture(0.02% of active ingredient) prepared from the active ingredientformulated as a wettable powder. The treated plants are dusted withconidia of the fungus after 3-4 hours. The infected barley plants arethen stood in a greenhouse at about 22° C. The extent of the infestationis evaluated after 10 days.

(b) Systemic action

Barley plants about 8 cm in height are treated with a spray mixture(0.006% of active ingredient, based on the volume of the soil) preparedfrom the active ingredient formulated as wettable powder. Care is takenthat the spray mixture does not come in contact with the parts of theplants above the soil. The treaated plants are infected 48 hours laterwith a conidia suspension of the fungus. The infected barley plants arethen stood in a greenhouse at about 22° C. and evaluation of infestationis made after 10 days.

In residual-protective treatment of barley plants against Erysiphe fungiwith compounds of the formula I, e.g. compounds 1.1, 1.2, 1.3, 1.4, 1.5,1.6, 1.7, 1.8, 1.13, 1.16, 1.38 or 1.71, attack is reduced to less than10% compared with controls (100% attack). In addition, compounds 1.1,1.2, 1.3, 1.4, 1.13, 1.38, 1.5, 1.6 and 1.8 have a very good systemicaction. Intermediates of the formula V and, in particular, of theformula VI (G=OSO₂ CH₃) exhibit fungicidal action in this test.

Groundnut plants 10-15 cm in height are sprayed with a wettable powdercontaining 0.02% of active ingredient and infected 48 hours later with aconidia suspension of the fungus. The infected plants are incubated for72 hours at about 21° C. and high humidity and then put into agreenhouse until the typical leaf specks occur. Evaluation of thefungicidal action is made 12 days after infection, and is based on thenumber and size of the specks. Compared with untreated controls (numberand size of the specks=100%), the plants treated with compounds of theformula I exhibit insignificant or almost no attack by fungus. Amongothers, compounds 1.1 to 1.9, 1.13 and 1.38 inhibit speck developmentalmost completely (0 to 5% attack).

EXAMPLE 8 Action against Puccinia graminis on wheat

(a) Residual-protective action

Wheat plants treated 6 days after sowing with a spray mixture preparedfrom a wettable powder formulation of the active ingredient (0.06%).After 24 hours the treated plants are infected with a uredosporesuspension of the fungus. The infected plants are incubated for 48 hoursat 95-100% relative humidity and about 20° C. and then stood in agreenhouse at about 22° C. Evaluation of rust pustule development ismade 12 days after infection. Among others, compounds 1.1, 1.2, 1.13,1.3, 1.5, 1.6 and 1.8 have a good residual-protective action. Theyinhibit rust pustule development almost completely (0 to 5% attack).

(b) Systemic action

Wheat plants are treated 5 days after sowing with a spray mixtureprepared from a wettable powder formulation of the active ingredient(0.006%, based on the volume of the soil). After 48 hours the treatedplants are infected with a uredospore suspension of the fungus. Theplants are then incubated for 48 hours at 95-100% relative humidity andabout 20° C. and then stood in a greenhouse at about 22° C. Evaluationof rust pustule development is made 12 days after infection. Amongothers, compounds 1.1, 1.2, 1.3, 1.13, 1.38, 1.5 and 1.8 inhibited rustpustule development almost completely (0 to 5% attack).

EXAMPLE 9 Residual-protective action against Venturia inaequalis onapple shoots

Apple cuttings with 10-20 cm long fresh shoots are sprayed with a spraymixture prepared from a wettable powder formulation of the activeingredient (0.06%). After 24 hours the treated plants are infected witha conidia suspension of the fungus. The plants are then incubated for 5days at 90-100% relative humidity and stood in a greenhouse for afurther 10 days at 20°-24° C. Scab infestation is evaluated 15 daysafter infection. Compounds of the formula I are very effective againstVenturis pathogens. Compounds 1.1, 1.2, 1.3, 1.13, 1.38, 1.4, 1.5 and1.6 in particular inhibit scab infestation to less than 20% comparedwith untreated controls. Compounds 1.3, 1.4, 1.13, 1.38 and 1.5 do soeven in a concentration of 0.02%.

What is claimed is:
 1. A compound of the formula I ##STR61## whereineach of R₁ and R₂ independently is hydrogen, C₁ -C₈ alkyl, unsubstitutedor mono- or polysubstituted by halogen, C₁ -C₄ alkoxy, C₁ -C₄ alkylthio,phenyl or phenoxy, or is phenyl, all of which phenyl radicals areunsubstituted or mono- or polysubstituted by halogen, nitro,trifluoromethyl, C₁ -C₄ alkyl or methoxy, or R₁ and R₂ together form a3- to 7-membered cycloalkyl ring which is unsubstituted or substitutedby halogen, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or C₁ -C₃ alkylthio, A is aphenyl radical unsubstituted or mono- or polysubstituted by halogen,trifluoromethyl, nitro, C₁ -C₄ alkyl, C₁ -C₄ alkoxy or phenyl, and X is--CH═ or --N═, or an acid addition salt thereof with organic orinorganic acids, or a metal complex salt thereof.
 2. A compoundaccording to claim 1, wherein each of R₁ and R₂ independently ishydrogen, C₁ -C₈ alkyl, phenyl which is unsubstituted or substituted byhalogen, nitro, trifluoromethyl, methyl or ethyl, or is benzyl.
 3. Acompound according to claim 2, wherein each of R₁ and R₂ independentlyis hydrogen, C₁ -C₅ alkyl or phenyl, and A is phenyl, unsubstituted ormono- or polysubstituted by halogen, C₁ -C₃ alkyl, methoxy or phenyl. 4.A compound according to claim 3, wherein each of R₁ and R₂ independentlyis C₁ -C₅ alkyl, and A is phenyl, 2,4-dichlorophenyl, 2,4-dibromophenyl,4-chlorophenyl, 2-chloro-4-fluorophenyl or 4-bromophenyl.
 5. A compoundaccording to claim 1, wherein R₁ and R₂ together form a 3- to 7-memberedcycloalkyl ring which is unsubstituted or substituted by methoxy.
 6. A1,2,4-triazolyl derivative of the formula I according to claim
 1. 7. Acompound according to claim 1, selected from the group consisting of4-(1H-1,2,4-triazolylmethyl)-4-(4-chlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,4-(1H-1,2,4-triazolylmethyl)-4-(4-bromophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,4-(1H-1,2,4-triazolylmethyl)-4-(phenyl)-2,2-dimethyl-1,3-dioxolan-5-one,4-(1H-1,2,4-triazolylmethyl)-4-(2,4-dichlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,4-(1H-imidazolylmethyl)-4-(4-chlorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one,4-(1H-1,2,4-triazolylmethyl)-4-(4-chlorophenyl)-2,2-diethyl-1,3-dioxolan-5-one,or4-(1H-1,2,4-triazolylmethyl)-5-(2-chloro-4-fluorophenyl)-2,2-dimethyl-1,3-dioxolan-5-one.8. A composition for regulating plant growth and/or for controllingand/or preventing attack by microorganisms, said composition containinga compound according to claim 1 as at least one active component and acarrier.
 9. A composition according to claim 8 which contains 0.01 to90% by weight of the compound and 99.99 to 10% by weight of adjuvants,which latter include 0 to 30% by weight of a surfactant.
 10. A method ofregulating plant growth, which method comprises applying to said plantsor to the locus thereof a herbicidally effective amount of a compoundaccording to claims 1 or
 7. 11. The method of claim 10 for inhibitingthe growth of cereals or grasses.
 12. The method of claim 10 forincreasing the yield of cereal, soybean, sugar beet, maize or ricecrops.
 13. The method of claim 10 for increasing the breaking strengthof wheat, rye, barley, oats or rice.
 14. A method of controlling and/orprotecting cultivated plants from attack by phytopathogenic fungi, whichmethod comprises applying to said plants or to the locus thereof afungicidally effective amount of a compound according to claims 1 or 7.15. The compound according to claim 7 which is4-(1H-1,2,4-triazolylmethyl)-4-(4-bromophenyl)-2,2-dimethyl-1,3-dioxolan-5-one.16. The compound according to claim 4 which is4-(1H-imidazolylmethyl)-4-(4-chlorophenyl)-2,2-diethyl-1,3-dioxolan-5-one.